Connecting adapter for electric cable and fuse

ABSTRACT

An adapter for connecting an electric cable to a blade-type fuse characteristic by an extruded metal body having at least one cable-receiving aperture with a set screw threadedly seated in the body and movable into the aperture, and a pressure bar for clamping the blade of a fuse in a tight-fitting surface-tosurface contact with the body.

Unitd States Patent 1 Wallace et al. [4 1 May 29, 1973 41 CONNECTINGADAPTER FOR [56] References Cited 5 [ELECTRIC CABLE AND FUSE UNITEDSTATES PATENTS t s [7 ms 2 23:? tfg g g 850,836 4/1907 Homsby et al...337/187 4 3,375,409 3/1968 Sturdivan ..339/272'A [73] Assignee:Westinghouse Electric Corporgfion, 3,629,806 l2/l97l Wiechrnann..339/272R I Pittsburgh, Pa. Primary Examiner-Joseph H. McGlynn [22]1972 Att0rneyA. T. Stratton, Clement 'L. McHale and [2]] Appl. No.:228,133 L. P. John v 52 us. c|... ..339/265 r, 337/7, 339/147 R, [57]ABSTRACT 339/272 R An adapter for connecting an electric cable to a [51]Int.,Cl. ..H0lr 7/26 blade-type fuse characteristic by an extruded metalField of Search 339/147, 242, 263, body having at least onecable-receiving aperture with a set screw threadedly seated in the bodyand movable 'into the aperture, and a pressure bar for clamping theblade of a fuse in a tight-fitting surface-to-surface'contact with thebody. I I I 10 Claims, 5 Drawing Figures PATENTEDmzs ms FIG.|.

FIG.5.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to an adapter for connecting one end of a blade-type fuse to anelectric cable.

2. Description of the Prior Art In the past, fusible switch equipment,such as panelboard switches, safety switches, and disconnect switches,have been provided with fuse jaws that have helper springs in order toobtain a reliable connection between the jaws and the blade of ablade-type fuse. To avoid overheating between the blade and the fusejaws, helper springs are necessary to maintain pressure in the jaws tocarry the current. As a result, there have been such widespreaddifficulties of inserting the blade between the fuse jaws, that is hasoften become necessary to drive the blades into the jaws with a malletor other appropriate tool. One disadvantage of using such force fordriving the fuse blade into place is that the jaws are mounted oninsulating bases of resinous material which is readily breakable.

Associated with the foregoing have been problems of assembly andproduction costs of the switches having fuse jaws adapted to acceptblade-type fuses.

SUMMARY OF THE INVENTION It has been found in accordance with thisinvention that the foregoing problems 'may be overcome by providing anadapter for connecting one or more electric cables to a blade type fusewhich adapter includes an extruded metallic body having first clampingmeans for holding one or more electric cables in electrical contact withthe body, and having second clamping means for holding the blade of ablade-type fuse in contact with the body; the first clamping meanscomprising at least one cable-receiving aperture and a setscrewthreadedly seated in the body and movable into the apertureforcompressing the cable in placeyand the second clamping meanscomprising a pressure bar with at least one bolt threadedly seated inthe body for holding the bar in tight-fitting engagement with the bladeof a fuse.

The advantage of the adapter is that it combines a fuse clamp and a wireor cable terminal into one extruded body and avoids an electrical jointand a source of heat. An ancillary advantage to the foregoing is areduction in the number of parts otherwise required.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side .elevational view,with parts broken away, of an electrical control structure comprising anenclosed fusible distribution switch and an improved adapter inaccordance with the principles of this invention;

FIG. 2 is an enlarged end view of the adapter taken on the line II-II ofFIG. 1;

FIG. 3 is an enlarged plan view of the adapter taken on the line III-IIIof FIG. 1';

FIG. 4 is an end view of another embodiment of the adapter; and

FIG. 5 is an end view of a second embodiment of the adapter. I

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, a fusibledistribution panelboard switch structure is generally indicated at 10,and it includes a switch generally indicated at 12, a blade-type fuse14, an adapter or connector 16, all of which are contained within a boxor enclosure 18. The fusible distribution panelboard switch structure 10may be used, for example, between one or more cables 20 and a bus bar(not shown) where the structure 10 is provided for branch switch use.

The switch 12 is of conventional structure having, amongother things, astationary contact 22, a movable contact 24, a switch handle 26, and aZ-type conductor bar 28. The switch 12 is manually operated from outsideof the enclosure 18 by means of an external operating handle 30 which isrotatably mounted on a removable front panel 32 of the enclosure tooperate an actuating member 34 that is mounted on the inner side of thefront panel. The actuating member 34 operatively connects the externalhandle 30 with the switch handle 26.

The enclosure 18 is usually mounted on a panelboard (not shown) on theside opposite the front panel 32.

The blade-type fuse 14 includes blades 36 and 38'at opposite endsthereof, the former of which is attached or secured to the conductor bar28 in a suitable manner such as a bolt-clamp 40. The blade 38 isconnected to the adapter 16in a manner. specifically described below.

The adapter 16 is shown more particularly in FIGS. 2 and 3 and isadapted for providing a'more suitable connection between the cable 20and the blade 38 of a fuse 14 than has been available heretofore. Theadapter 16 is composed of an electrically conductive material and ispreferably a metal body such as an extrusion of aluminum or copper. Assuch, the adapter 16 is provided with a pair of similar spaced openings42 and 44 as well as a clamping surface 46. The adapter may also beprovided with an opening 48in the center thereof for minimizing theweight of the adapter. The adapter 16 is preferably provided with a pairof spaced threaded openings 50 by which the adapter is secured in placewithin the enclosure 18. For that purpose, a pair of similar bolts 52extend through a bottom panel of the enclosure 18, the inner surface ofwhich isprovided with a base 54 of electrically insulating material.

The openings 42 and 44 are generally circular or elliptical intransverse cross-section and are adapted to receive one or more cables20. Each opening 42 and 44 is provided with a setscrew 56 which isseated in similar threaded openings 58. The openings 58 have axes whichpreferably extend through or intersect the longitudinal axes of theopenings 42 and 44 so that when the setscrew 56 are tightened, the innerends thereof clamp the cables 20 in place against the surface of theopenings as shown in FIG. 2. Accordingly, the combination I of eachopening and said screw in the adapter 16 constitutes clamping means forholding an electric cable in electrical contact with the body of theadapter. 1

As shown more particularly in FIGS. 2 and 3, a pressure bar 60 is usedin conjunction with the clamping surface 46. Each end of the bar 60 isapertured to receive a tightening bolt 62for applying pressure to theblade 38 of the fuse 14. Each bolt 62 is seated in a th}eaded opening 64in the adapter. Thus, the combin tion of the clamping surface 46, thepressure bar 60, and the bolts 62 constitutes clamping means for holdingthe fuse blade 38 in contact with the adapter 16. Inasmuch as theadapter 16 is an integral metal body composed of a metal, such asaluminum or copper, a highly conductive current path is provided betweenthe cables 20 and the blade 38 of the fuse 14.

As shown in FIG. 3, the clamping bar 60 is spaced longitudinally alongthe axis of the openings 42 and 44 from the setscrews 56.

Another embodiment of the invention is shown in FIG. 4 wherein anadapter 66 is provided with a single opening 68 for receiving the cable20. The body of the adapter 66, through which the opening 68 extends,includes a pair of flanges 70 and 72, the former of which provides aclamping surface 74 and the latter of which is provided with similarspaced threaded openings 76 in a manner similar to the openings 50 ofthe adapter 16. In other respects, the adapter 66 is similar to theadapter 16 in that it is provided with a pressure bar 60 with associatedbolts 62 for clampingly engaging the blade 38 of a fuse. Likewise, thesetscrew 56 cooperates with the opening 68 to clampingly engage thecable 20, in a manner similar to that shown in FIG. 2.

A third embodiment of the invention is shown in FIG. wherein a pair ofspaced members 78 and 80 are disposed on opposite sides of a fuse blade82 and in clamping engagement therewith. For that purpose, spacedtightening bolts 84 and 86 extend between juxtaposed flanges 88 and 90,and flanges 92 and 94, respectively. The flanges 88 and 92 are integralparts of the member 78, and the flanges 90 and 94 are integral parts ofthe member 80. The flange 94 includes an outturned portion 96 by whichthe assembly of the members 78 and 80 may be attached to a wall of theenclosure 18 by suitable means such as a bolt 98. In other respects, themembers 78 and 80 resemble the adapter 16 in that they are provided withsimilar openings 42 and 44 as well as with corresponding setscrews 56 bywhich cables 20 may be clampingly engaged in a manner set forth above.

Accordingly, the adapter or connector of the present invention satisfiesdisadvantages associated with prior art devices, and provides a moreeconomical means of combining fuse clamps and wire or cable terminalsinto an extruded adapter whereby electrical joints which otherwise serveas sources of overheating are avoided.

It is to be noted that both embodiments of the invention shown in FIGS.2 and 4 include two spaced parallel portions at least one of whichportions, such as flange 76 in FIG. 4, is provided with opening meansadapted to mounting the adapter on a support member.

CROSS-REFERENCE TO RELATED APPLICATION This invention relates to theinvention disclosed in the application of John E. Grad, Ser. No.228,134, filed Feb. 22, 1972.

What is claimed is:

1. An adapter for connecting an electric cable to a blade-type fuse, theadapter comprising a single unitary metal body having first clampingmeans for holding an electric cable in electrical contact with the body,the metal body having second clamping means for holding the blade of ablade-type fuse in contact with the body, and the body having at leasttwo spaced parallel portions, one of which portions is provided withopening means for mounting the body on a support member.

2. The adapter of claim 1 in which the first clamping means comprisesaperture means for receiving an electric cable.

3. The adapter of claim 2 in which the first clamping means comprisesset screw means extending through the body and into the aperture meansfor clampingly engaging an electric cable in the aperture means.

4. The adapter of claim 1 in which the first clamping means comprises atleast one cable-receiving aperture and a set screw threadedly seated inthe body and movable into the aperture.

5. The adapter of claim 4 in which the body includes a clamping surfaceand the second clamping means comprises a'bar and bar-mounting bolts foradjustably mounting the bar at varying distances from the clampingsurface. g I

6. The adapter of claim 4 in which the second clamping means comprises apressure bar, and in which the set screw and pressure bar are spacedlongitudinally of the axis of the aperture.

7. The adapter of claim 1 in which the secondclamping means comprisespressure bar and means for mounting the bar on the body.

8. The adapter of claim 7 in which the body includes a clamping surfaceengageable with a blade of a bladetype fuse when the blade is clamped inplace between the surface and the bar.

9. The adapter of claim 7 in which the means for mounting the barcomprises at least one bolt threadedly seated in the body.

10. The adapterof claim 9 in which the body includes two cable-receivingapertures and the clamping surface is disposed in a plane substantiallyparallel to the axes of the apertures.

1. An adapter for connecting an electric cable to a blade-type fuse, theadapter comprising a single unitary metal body having first clampingmeans for holding an electric cable in electrical contact with the body,the metal body having second clamping means for holding the blade of ablade-type fuse in contact with the body, and the body having at leasttwo spaced parallel portions, one of which portions is provided withopening means for mounting the body on a support member.
 2. The adapterof claim 1 in which the first clamping means comprises aperture meansfor receiving an electric cable.
 3. The adapter of claim 2 in which thefirst clamping means comprises set screw means extending through thebody and into the aperture means for clampingly engaging an electriccable in the aperture means.
 4. The adapter of claim 1 in which thefirst clamping means comprises at least one cable-receiving aperture anda set screw threadedly seated in the body and movable into the aperture.5. The adapter of claim 4 in which the body includes a clamping surfaceand the second clamping means comprises a bar and bar-mounting bolts foradjustably mounting the bar at varying distances from the clampingsurface.
 6. The adapter of claim 4 in which the second clamping meanscomprises a pressure bar, and in which the set screw and pressure barare spaced longitudinally of the axis of the aperture.
 7. The adapter ofclaim 1 in which the second clamping means comprises pressure bar andmeans for mounting the bar on the body.
 8. The adapter of claim 7 inwhich the body includes a clamping surface engageable with a blade of ablade-type fuse when the blade is clamped in place between the surfaceand the bar.
 9. The adapter of claim 7 in which the means for mountingthe bar comprises at least one bolt threadedly seated in the body. 10.The adapter of claim 9 in which the body includes two cable-receivingaperTures and the clamping surface is disposed in a plane substantiallyparallel to the axes of the apertures.